“Alkyl-Substituted\nPhenoxy” Spacer Strategy:\nAntiaggregated and Highly Soluble Zinc Phthalocyanines for Color Films

A series of zinc phthalocyanine derivatives (ZnPcs) were\ndesigned\nby introducing different volumes of steric hindrance groups (chlorine\natom, n-propyloxy, isopropyloxy, n-butoxy, isobutoxy, <i>tert</i>-butoxy, 2,4-di-<i>tert</i>-butylphenoxy, 2,4-di-<i>tert</i>-pentylphenoxy) on the peripheral and nonperipheral\npositions of phthalocyanine. Density functional theory (DFT) calculations\npresented that the substitution of sterically hindered 2,4-di-<i>tert</i>-butylphenoxy or 2,4-di-<i>tert</i>-pentylphenoxy\non the peripheral positions effectively reduced the aggregation of\nZnPcs, improving the solubility of ZnPcs, and the simultaneous substitution\non the peripheral and nonperipheral positions could achieve ZnPcs\nwith different colors. From the calculation results, six low-aggregation\nZnPcs were synthesized for the first time. The solubilities of the\nsynthesized ZnPcs are above 6.0/100 g. Furthermore, their color films\ndisplayed excellent transmittance because of the introduction of sterically\nhindered 2,4-di-<i>tert</i>-butoxyphenoxy or 2,4-di-<i>tert</i>-pentylphenoxy moieties. Also, the color films exhibit\ngreat photo and thermal stability (Δ<i>E</i> <\n3).